Hyman Roth tells Michael that Moe Green's death had nothing to do with business, so he never asked "who gave the order." By implication he is chastising Michael for asking him who had Frank Pentangeli killed, and is implying that it had nothing to do with business.

In fact, both deaths had everything to do with business. The Corleones had to move Roth out to take over his hotel, and by definition establish a presence in Las Vegas where Roth had interests. Pentangeli was holding back the Rosato brothers efforts to get control of new territories as Clemenza had promised them, and about which Pentangeli welched.

Indeed this nonsensical rant is further curious because I thought
the rules of the game were that you could kill people if it had something to do with business, and if it was nothing personal.

So why is Roth mad if in his opinion Green's death had nothing to do with business?